Honeywell T874 - Schematic and Hookup of T874 A-F, Q with Q674 G. Used in Standard Applications; Schematic and Hookup of T874 C, D with Q674 G. Used Heat Pump Applications

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8 120
Fig. 91. Schematic and hookup of T874A-F,Q with Q674G. Used in standard applications.
Fig. 92. Schematic and hookup of T874C with Q674G. Used in heat pump applications.
H1
FALL
L1
(HOT
)
L2
1
RH
W1
W2
O
Y2
Y1
RC
HEAT RELAY 2
HEAT RELAY 1
OFF
AUTO
SYSTEM
SWITCH
H1
ANTICIPATOR
C1 ANTICIPATOR
NO FAN
SWITCH
2
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
JUMPER RH, RC FOR SINGLE TRANSFORMER.
2
M3201B
L1
(HOT
)
L2
1
COOL DAMPER
HEAT DAMPER
COMPRESSOR
CONTACTOR 2
COMPRESSOR
CONTACTOR 1
1
4
6
8
9
10
11
H2
FALL
C2 ANTICIPATOR
RISE
RISE
C1
C2
B
THERMOSTAT
SUBBASE
SYSTEM COMPONENTS
H2 ANTICIPATOR
L2
1
OFF
H1 ANTICIPATOR
H2 ANTICIPATOR
H1
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
M6008A
Y1
W1
C1 ANTICIPATOR
AUTO
FALL
FALL
CHANGEOVER
RELAY
L1
(HOT
)
R
FAN RELAY
COMPRESSOR
CONTACTOR
G
3
THERMOSTAT SUBBASE SYSTEM COMPONENTS
NO FAN
SWITCH
SYSTEM
SWITCH
RISE
H2
W2
B
1
4
6
8
9
10
C1